Improvement in metallic columns



UNITED STATES PATENT OFFICE.

JOHN L. PIPER, OF PITTSBUBG, PENNSYLVANIA.

IMPRovEMENT IN METALLIC COLUMNS.

Specification forming part of Letters Patent No. 138,817, dated May 13, 1873; application filed April 11, 1873.

To all whom it may concern:

Be it known that I, JOHN L. PIPER, ot' Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Metallic Posts; and I do hereby declare the following to be a full, clear, and exact description thereof, reference being had to the accompanying drawing making a part of this specification, in whichf Figure l is a perspective view of a portion of a hollow column made in accordance with my improvement; and Figs. 2 and 3, by like views, illustrate the same improvement in moditied forms.

My improvement relates to the construction of a hollow post, column, strut, or girder, suitable for use in connection with bridges, buildings, and other heavy structures; and consists in combining a series of curved plates, made each with a rib along the edge ot' each outer face, ot' such form that when the plates are brought together edge to edge the contiguous ribs will form the male part of a dovetail, over which is placed strips, clips, or clamps, having recesses of correspondin g dovetail-form, whereby the curved plates are secured together.

`'Io enable others skilled in the art to make and to use my invention, I will proceed to describe its construction and manner of use.

The plates B are rolled in suitably-shaped rolls to the curved form shown, and ofthe desired width' and thickness, and with a rib, a, along the outer edge of the convex face of each pla-te said ribs having each a greater breadth on its outer face than at its base, as shown, so that when the plates are brought together,

as in Fig. l, two contiguous ribs, o a, will form the male halt' of a dovetail-joint. The

plates B are then secured together by strips D, as shown in Fig. l; which strips are made, externally, of suitable form, and, internally, with longitudinal recesses of suitable shape to slip onto and clamp the ribs t a, and thereby form a secure dovetail-joint and hold the plates together; or, instead of the strips D, clips or clamps Dl may be employed, as illustrated in Fig. 2; and such clips are held from slipping down on the ribs a by means of setscrews d or other suitable device. When it is desired to spread the post, either throughout its whole length or at its middle part, it may be done in the manner illustrated in Fig. 3, where the clips p are made so as to clamp onto the ribs a, as already described, and also with inwardly-projecting lugs p p', which, when the devices are put together, come between the edges of the plates B and hold them at the proper distance apart. .These clips are held in place by means of set-screws d, as before. The plates B may be made in any desired number-two or more. The spread of the ribs a, in taking the dovetail form, should not be so great as to prevent the ready delivery ot' the plates from the rolls. rIhe recesses in the strips D may be conveniently made by planing, and the recesses in the clips D may be made in like manner; or, if the clips be cast, they may be made in the usual way employed in casting. Instead of the strips D or the clips D any known device suitable for binding together the dovetail-shaped ribs a may be employed.

What I claim as my invention, and desire to secure by Letters Patent, is-

l. As a'component part ot' a hollow post, column, strut, or girder, a plate, B, rolled to a curved form, and with lugs a rolled on each edge of the outer face, such lugs being broader on their outer face than at their bases, whereby, when two or more such plates are brought edge to edge, with or without distance pieces p the two contiguous lugs will form the male part of a dovetail-joint, substantially as set forth.

2. The hollow post, column, strut, or girder composed of three or more plates, B, secured together by means ot' any known suitable device, arranged on the dovetail-shaped ribs a, substantially as set forth.

In testimony whereof I, the said JOHN L. PIPER, have hereunto set my hand.

J. L. PIPER. Witnesses:

A. S. NIoEoLsoN, G. H. CHEIsTY. 

